Acoustical testing apparatus

ABSTRACT

Testing apparatus for hearing aids and the like has an outer cabinet enclosed by a top, bottom and sides within which is a horn-shaped anechoic inner chamber that encloses the component to be tested, which chamber is formed of sound absorbing panels, having a smooth interior surface, and which increase in thickness from the top towards the bottom. Said chamber has a bottom and a well is formed below the bottom that communicates with the chamber and is of greater width at the point of communication. A cover for said chamber is lined with wedge-shaped sound absorbing panels that extend from the top downwardly.

FiPslia UR newness .jEfn'l'fi-i ROOM United States Pate 1. t t 1111 3,876,035

Eckel Apr. 8, 1975 ACOUSTICAL TESTING APPARATUS Primary Eraminer-Richard B. Wilkinson Assistant Examiner-John F. Gonzales l tzAl EkLW fd,M.. [75] men or an c e est or ass Attorney, Agent. or Firm-Harold E. Cole [73] Assignee: Eckel Industries, Inc., Qambridge.

Mass- 57 ABSTRACT [22] Filed: May 13, 1974 Testing apparatus for hearing aids and the like has an outer cabinet enclosed by a top, bottom and sides within which is a horn-shaped anechoic inner chamber that encloses the component to be tested, which 211 Appl. No.: 469,299

[52] U.S. Cl. 181/33 GE h m er i formed of sound a r ing p n l h ing [51] Int. Cl E04b 1/84 a smooth interior surface, and which increase in thick- [58] Field of Search 181/33 GD, 33 GE, 33 K; ness from the top towards the bottom. Said chamber 73/552; 343/18 A; 179/107 R, 175 has a bottom and a well is formed below the bottom that communicates with the chamber and is of greater [56] References Cited width at the point of communication. A cover for said UNITED STATES PATENTS chamber is lined with wedge-shaped sound absorbing 3.295.133 l2/l966 Emerson et a]. 181/33 GE Panels that extend from the downwardly 7 Claims, 6 Drawing Figures ACOUSTICAL TESTING APPARATUS The principal object of my invention is to provide an improved anechoic zone in said chamber by an assembly of panels to accurately measure the response characteristics of hearing aids, small microphones and the like, said zone communicating with a well below said chamber.

Another object is to economize in material by forming the chamber with panels at the sides that present a smooth, even internal surface, thus avoiding the expense entailed by using wedge-shaped or other irregularly-shaped pieces.

The foregoing and other objects which will appear as the nature of the invention is better understood, may be accomplished by a construction, combination and arrangement of parts such as is disclosed by the drawing. The nature of the invention is such as to render it susceptible to various changes and modifications, and therefore I am not to be limited to the construction disclosed by the drawing, nor to the particular par'ts described in the specification; but am entitled to all such changes therefrom as fall within the scope of my invention.

In the drawing:

FIG. I is a perspective view of my testing apparatus with a cover thereon.

FIG. 2 is a perspective view of said testing apparatus with the cover removed.

FIG. 3 is a sectional view taken on the line 3-3 of FIG. 5.

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 2.

FIG. 5 is a sectional view taken on the line 5-5 of FIG. 1.

FIG. 6 is a sectional view taken on the line 66 of FIG. 5.

As illustrated, my acoustical testing apparatus has an outer housing or cabinet 10 having a bottom plate 12 from which side or wall means extend upwardly, there being four sides 14, 16, 18 and 20 shown. A hearing aid 22, for instance, may be supported by two of said sides, as shown in said FIG. 2.

Within said outer housing 10 is a sound absorbing anechoic chamber 24 having side means shown as a wall 26 formed of panels 28 laid together side-by-side, which panels may be made of fiberglass or other sound absorbing material. A bottom 30 supports said wall 26 and it has an intermediate opening 32. A well 34, having side means or a wall 36, extends downwardly from said bottom 30 and it has a bottom 38 connected to said sides. Said well 34 is lined with sound absorbing material 40, and it communicates with said chamber opening 32, being ofgreater area thereof, being rectangular and its four sides each preferably is wider than the latter opening as shown in said FIG. 4. A loud speaker 41 is received in said well 34, resting on said bottom 38. Said panels 28 extend from the chamber bottom 30 straight upwardly as at 42 to an intermediate portion of said chamber as at 43 and then flare outwardly and upwardly as at 44, gradually reducing in thickness, until they terminate at the upper portion of said outer housing 10 as at 45. These panels 28 may be a few inches wide, such as 4 inches, and they present a continuous even or smooth inner surface throughout the chamber wall.

A cover 48 for said chamber has a top 50 from which four sides 52 depend downwardly. It is lined by wellknown insulating members 54 which are wedge-shaped and extend downwardly from said top in well-known alternating positions such as shown in said FIGS. 3 and 5. Said cover sides 52 are lined with insulating material 56 which extend from the inner surfaces thereof completely around said cover.

In use my apparatus is operably associated in the usual way with well-known equipment to measure and evaluate a component to be tested. Said component and a loud speaker are placed in said chamber and well respectively. The loud speaker would be connected to a well-known external oscillator and amplifier and hearing aid attached to a microphone by means of a coupler. The microphone is connected to a sound meter and analyzer by which the gain and frequency response can be measured.

What I claim is:

l. Acoustical testing apparatus comprising an outer housing, a sound absorbing chamber within said outer housing having a bottom and a horn-shaped, anechoic chamber extending upwardly from said bottom and formed 'of panels in side-by-side relationship and flaring outwardly towards the top, said panels having a smooth, interior surface and varying in thickness, the lowest portions thereof being thicker than the portions forming the top of said chamber.

2. Acoustical testing apparatus as set forth in claim 1, portions of said panels extending from said lowest portions straight upwardly and portions extending up wardly from the latter flaring outwardly and terminating at a point adjacent the top and side of said housing.

3. Acoustical testing apparatus as set forth in claim 1, said chamber bottom having an opening spaced inwardly from the outer side extremity thereof, and a well member extending lower than said opening having an interior space extending downwardly from said bottom and communicating with said chamber opening, said well member having side means extending downwardly from said chamber bottom and a bottom connected to and extending from and between said latter side means.

4. Acoustical testing apparatus as set forth in claim 3, said well member and its interior space extending laterally beyond said chamber opening.

5. Acoustical testing apparatus as set forth in claim 3, and sound absorbing material extending inwardly of and in contact with said well member side means and bottom.

6. Acoustical testing apparatus as set forth in claim 3, said housing having a bottom plate below said well bottom and communicating with said well interior space.

7. Acoustical testing apparatus as set forth in claim 1, and a cover for said housing having wedge-shaped, insulating members extending downwardly from said cover and being spaced from the lower extremity 

1. Acoustical testing apparatus comprising an outer housing, a sound absorbing chamber within said outer housing having a bottom and a horn-shaped, anechoic chamber extending upwardly from said bottom and formed of panels in side-by-side relationship and flaring outwardly towards the top, said panels having a smooth, interior surface and varying in thickness, the lowest portions thereof being thicker than the portions forming the top of said chamber.
 2. Acoustical testing apparatus as set forth in claim 1, portions of said panels extending from said lowest portions straight upwardly and portions extending upwardly from the latter flaring outwardly and terminating at a point adjacent the top and side of said housing.
 3. Acoustical testing apparatus as set forth in claim 1, said chamber bottom having an opening spaced inwardly from the outer side extremity thereof, and a well member extending lower than said opening having an interior space extending downwardly from said bottom and communicating with said chamber opening, said well member having side means extending downwardly from said chamber bottom and a bottom connected to and extending from and between said latter side means.
 4. Acoustical testing apparatus as set forth in claim 3, said well member and its interior space extending laterally beyond said chamber opening.
 5. Acoustical testing apparatus as set forth in claim 3, and sound absorbing material extending inwardly of and in contact with said well member side means and bottom.
 6. Acoustical testing apparatus as set forth in claim 3, said housing having a bottom plate below said well bottom and communicating with said well interior space.
 7. Acoustical testing apparatus as set forth in claim 1, and a cover for said housing having wedge-shaped, insulating members extending downwardly from said cover and being spaced from the lower extremity thereof upwardly. 